Crossrail is Europe’s biggest infrastructure project. Budgeted at £14.8 billion — £12 billion of which is going on 42km of tunnels — the underground part of the line will stretch from Royal Oak in west London to Plumstead in the south-east. “The scale is immense,” says Andy Mitchell, Crossrail programme director. The 1,000-tonne tunnel-boring machines (TBMs), which were made by German firm Herrenknecht in Schwanau, travelled from Rotterdam to Essex by ferry last year.

Six are “earth pressure balance” machines for tunnelling through clay; two are “slurry” machines for the chalk, flint and water found under south-east London.

Pulling power: the tunnel borer tows a trailer containing the operator’s cabin, as well as up to 10 sledges (pictured). The sledges roll on wheels over the finished tunnel, carrying equipment, material, a kitchen and a refuge chamber

One of the slurry machines, TBM6, is currently on a 2.6km drive from Plumstead, passing under the Thames to North Woolwich. (Traditionally, each tunnelling machine is given a female nickname — TBM6 is called Mary, after Isambard Kingdom Brunel’s wife.)

Heavy lifting: this scoop can raise material to the surface from 25m down at the bottom of the five-storey Bond Street subterranean ticket hall, which comes within 3m of the existing Jubilee line tunnel

It operates 24 hours a day, every day, and is staffed by a 20-strong gang working 12-hour shifts. Powered by electricity from the national grid, the cutter head rotates three times a minute. The tunnel is then lined with concrete rings — at a rate of 10 a day — composed of seven segments and a keystone which have been lowered into the shaft from where the tunneling machine was launched, then carried on a small locomotive.

Track work: tunnel segments are transported to the tunnel boring machine on these tracks. The pipes on the left deliver water and carry away slurry

If stoppages are kept to a minimum, TBM6 will be in North Woolwich by the summer of 2014. All the tunnels are due to be completed by the end of next year, at which point the stations, overground sections and fit-out will become the focus. The first trains are due to run in 2018.

Photography by Christoffer Rudquist

Holy help: in accordance with tradition, St Barbara, the patron saint of miners, watches over the entrance to the tunnel at Plumstead

CROSSRAIL BY NUMBERS

40 per cent

rise in house prices over the next five years predicted for houses within a 10-minute walk of central London’s nine Crossrail stations, according to estate agent Knight Frank

£14.8 billion

cost of Crossrail, 60 per cent of which will come from Londoners (through ticket revenue) and London businesses (through investment). The rest is from City Hall and a central government grant of £4.7 billion

8,000 people

working on 40 construction sites

100 metres

of tunnel excavated per week

6 million

tonnes of earth will be excavated by the eight tunnel-boring machines

250,000

concrete segments, each 1.6m wide, used to line the 42km of tunnels 39 minutes will be the journey time from Heathrow to Canary Wharf when the line opens in 2018

148

length in metres of the longest German-made tunnel-boring machine. Their cutters are 7m wide, they weigh 980 tonnes and are operated by 20 people each

135

age of the Connaught Tunnel under the Royal Docks, which will now be used again for Crossrail

September 2013 issue of WIRED

See the rest of this feature within the September 2013 issue of WIRED, out on Thursday.